Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design in accordance with a first embodiment;

FIG. 2 is a second image thereof;

FIG. 3 is a third image thereof;

FIG. 4 is a fourth image thereof;

FIG. 5 is a first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design in accordance with a second embodiment;

FIG. 6 is a second image thereof;

FIG. 7 is a third image thereof;

FIG. 8 is a fourth image thereof;

FIG. 9 is a first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design in accordance with a third embodiment;

FIG. 10 is a second image thereof;

FIG. 11 is a third image thereof; and,

FIG. 12 is a fourth image thereof.

The outermost broken lines in the figures illustrate the display screen or portion thereof. The remaining broken lines shown in the figures illustrate portions of the transitional graphical user interface. None of the broken lines form part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 